Direct conversion of cellulose to 5-hydroxymethylfurfural over SnNb2O6–ZrO2 catalyst

In this study, novel SnNb2O6–ZrO2 nanosheet composites were successfully synthesized by hydrothermal method and evaluated for the conversion of cellulose. As a result, the composite samples demonstrate excellent catalytic performance toward cellulose conversion to 5-hydroxymethylfurfural (H6MF), a crucial green platform chemical and excellent intermediate, in a bi-phase system of THF/H2O with the addition of NaCl. The SnNb2O–ZrO2 catalysts with different ZrO2 amounts were characterized by XRD, SEM, TEM, XPS, pyridine-FTIR and Raman to investigate the properties of the samples. The Lewis acid sites and Brønsted acid sites of the samples and the interaction between SnNb2O6 and ZrO2 were also discussed in this work. Since the reaction temperature, reaction time, NaCl amounts and the volume ratio of THF/H2O were altered, the highest conversion of cellulose achieved 85% over SnNb2O6–5% ZrO2 catalyst, with good selectivity (41.8%) and yield (35.5%) of HMF in THF/H2O (volume ratio of 3:1) within 6 h at 180 °C.